Spektrum Satelite Antennas

[kenobi36]

I have opened spektrum DSMX satelite and I noticed that it has only one antenna. Second is the weight.
So if both wires cannot go away from the frame into the air then we should stick the satelite such way so the real antenna will go into air.

On the photo right wire on the side where is the connector is the weight. Left is antenna.

[EEngineer]

Originally Posted by kenobi36

I have opened spektrum DSMX satelite and I noticed that it has only one antenna. Second is the weight.
So if both wires cannot go away from the frame into the air then we should stick the satelite such way so the real antenna will go into air.

On the photo right wire on the side where is the connector is the weight. Left is antenna.

What you said is not true.....it's a myth

Turn you're sat. over and post another pic showing the radio IC and I'll show you why it's not true.

FWIW

[KSHeli]

Originally Posted by EEngineer

What you said is not true.....it's a myth

Turn you're sat. over and post another pic showing the radio IC and I'll show you why it's not true.

FWIW

I seen many times that the left is the only active antenna, so are you saying both are active, or is only the left active?

[kenobi36]

Right one is connected to the ground. I have checked it with multimeter. Enyone can do it. Just don't forget to scratch the covering the solders glue.

Here You are Mr. EEngineer, what do you want to add? Did you made tests? Are You a real engineer? Why do you say its a myth? I have opened the satelite. Did you do it too?

[EEngineer]

Chill out...your pic doesn't show the radio IC part #...which cannot support your claim....which is why this myth keeps on keeping on....by those that aren't "real engineers".

Did you even bother to identify the Radio IC(which a real engineer would do)....which is the Cypress Semi CYRF6926...?

After IDing the IC, did you look at the data?

http://www.cypress.com/?docID=28606

Had you done so, you would know that both antenna elements are NOT connected to ground....either as described by Cypress Semi...and with independent verification...as my DVM shows that there is NO continuity between RFp and RFn and ground....and your claim, by your measuring, that either of the 2 dipole elements is grounded is false.

I have provided you with a link to the manufacturers specs...

I recommend that you replace the battery on your DVM.

Claim what you want, but the propogation of this erroneous info is detrimental to this hobby

FWIW

[kenobi36]

Most funny thing is that you dont even know You are talking about.
I told you that I have mesured it and one wire is soldered to the ground.
Here is the solder place for the second antena.
Ic number will not change anything if one antenna is soldered to the ground !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
FYI IC chip number is erased.


"propogation of erroneous info is detrimental to this hobby" - EEngineer - You are a proof of it.

[kenobi36]

Finally uploaded
Test1 - Base test with both antennas
Test2 - we can see terrible difference if we remove wire A1 which is antena.
Test3 - Satellite with removed X1 wire which is soldered to the ground - there is no difference to Test 1
Test4- Orange DSM2 receiver.

Spektrum DSMX Satellite antennas (6 min 38 sec)

[EEngineer]

Nice music in your video....

In direct contradiction to the data sheet of the CYRF6926 radio IC by Cypress Semi, this is your proof that one antenna element is grounded?

Did you happen to look over the data sheet?

Pages 1, 2, and 12 specifically.

What you've done is make a monopole antenna system from what was a dipole antenna system.

And what does your WiFi router have to do with your test? The whole purpose of DSMX, etc. is not to get RF interference.

Looks like your "test" with what you call the "ground" antenna works better than what you call the "real" antenna.

All your test shows is that the DSMX satellite is pretty robust, even when you "rip" off one of the dipole elements.....not that one dipole element is grounded.

You might want to look up what an H-Stub antenna is, which is what is used in the Spektrum as well as JR DSMX satellites.

Try this test........instead of removing what you refer to as the "ground" element, jumper it to system ground....with a clip-on lead from the antenna tip to ground.....

And see how your test works.

Also, why would a manufacturer spend the time and money to fabricate a PCB, spot components for H-Stub tuning purposes, solder them all in.....and then solder a 1.25" wire that flaps in the breeze that you claim is connected to ground?

FWIW

[dsduani]

This is a topic that has come up several times. I also thought that only one antenna was active but contacted Spektrum and they state that both antennaes are active.
See https://www.helifreak.com/showthread...light=antennae post #17 and 18

Quote from their email:
"Both antenna's are active on the satellite receiver. The most important aspect of mounting a satellite receiver is having the antenna's perpendicular to the main receiver antenna for better signal diversification. Always range test before flights to ensure signal strength. "

(I also learned that they recommend at least 3" between antennas if you have more than one mounted on the heli)

[ragge1]

http://www.archeli.com.au/forums/sho...d.php?t=136223

[EEngineer]

Originally Posted by ragge1

http://www.archeli.com.au/forums/showthread.php?t=136223

That's exactly where this myth got started.

And why I posted the data sheet for the radio IC.....which shows, via electrical circuitry, what Spektrum told dsduani verbally.

As I mentioned, simply attach a clip lead to the "ground antenna" element tip and then to system ground and see what happens.

[kenobi36]

You just trying to save your face.
You say that longer range is worse than shorter to excuse you erratic post.
But If you want I will make another test for you with clip, should I catch the wire or the isolation with a clip?
I'm sure it will be same range as two or one A1 wire which is the antenna.
And I'm sure you will find another excuse for saving your erratic post.
People Like You never give up even if its working bad for all other.

Regarding the router I wanted to show that the link is stable even if I move the receiver 30cm to the router. I had corona 2.4HHz DIY system in a past which was loosing link near router or other strong RF transmitters

[EEngineer]

"But If you want I will make another test for you with clip, should I catch the wire or the isolation with a clip?"

The tip of the wire to the system ground...where the black wire connects on your satellite RX.

Likewise, I will perform the same test later this evening with a satellite RX I have....but I will be using an AR7200BX instead of the RX you are using.

We can then compare results.

BTW, you're place is a mess...you should clean it up a bit.....

[ragge1]

been flying my 6HV with the antenna half cut from my last crash , no issues

[EEngineer]

Originally Posted by ragge1

been flying my 6HV with the antenna half cut from my last crash , no issues

Wow, you're braver than I am......

I read somewhere that Swedes were lucky....

I would have swapped that out faster than a "New York" minute.

It would be Interesting to "rotate" that satellite Rx....to see how it's antenna gain pattern differs from that expected from a normal dipole gain pattern......

I don't have an oscilloscope that operates at 2.4 GHz......the one I'd want would set me back about $5K....

Used to work at a place that had an "anechoic" chamber, in which we'd measure antenna gain patterns of a variety of antennas.

[mbutler6063]

http://searchmobilecomputing.techtar...-plane-antenna

I promise it's there for a reason....and it is connected to ground.

[kenobi36]

AR7200 has 2 antennas. Thats why they should be places 90 degree to each other.
Thats how works FrSky, Futaba, Spektrum AR400 AR610 AR635.
But not AR6210, satellite 9645.
Its logical that if they would have two active antennas then they woud be set 90 degree.
Its also logical that if 9645 would have two active antennas then carbon 9646 would also have two antennas.
Thats why AR400, 610, 635 is called full range. But AR6210 is full range only if it works with second receiver (second active antenna) which is satellite.

AR6210, satelite 9645is something what could be dipole antenna but its not proper bucause it has not proper length becouse we have to ad length of wire to the width of the electronic board which has ground area.

Originally Posted by EEngineer

"BTW, you're place is a mess...you should clean it up a bit.....

Organized chaos :-)

[EEngineer]

Originally Posted by mbutler6063

http://searchmobilecomputing.techtar...-plane-antenna

I promise it's there for a reason....and it is connected to ground.

Um, you posted a link that describes an antenna used for CB radios.

I posted a link showing the radio IC manufacturer's data sheet, which clearly shows to anyone that it's not connected to system ground.

FWIW

[EEngineer]

Originally Posted by kenobi36

AR7200 has 2 antennas. Thats why they should be places 90 degree to each other.
Thats how works FrSky, Futaba, Spektrum AR400 AR610 AR635.
But not AR6210, satellite 9645.
Its logical that if they would have two active antennas then they woud be set 90 degree.
Its also logical that if 9645 would have two active antennas then carbon 9646 would also have two antennas.
Thats why AR400, 610, 635 is called full range. But AR6210 is full range only if it works with second receiver (second active antenna) which is satellite.

AR6210, satelite 9645is something what could be dipole antenna but its not proper bucause it has not proper length becouse we have to ad length of wire to the width of the electronic board which has ground area.


Organized chaos :-)

Forget about the main Rx

Ground the tip on the satellite and see what happens

[EEngineer]

"AR6210, satelite 9645is something what could be dipole antenna but its not proper bucause it has not proper length becouse we have to ad length of wire to the width of the electronic board which has ground area."

Not true for an H-Stub dipole....by varying the spacing of the 2 dipole antenna input/output points on the PCB, RF phase shifts can be introduced that change the antenna gain pattern from that of a typical dipole antenna gain pattern.

This can optimize the antenna system, given this particular application.

Multiple gain pattern "lobes" can be had.....which, in 3D, looks something like a stack of donuts with antenna elements going through the donut holes.

More lobes = better gain at varying orientations of the satellite Rx to the Tx antenna.

With a typical dipole antenna system, the antenna gain is nulled when the antenna element approaches being lined up to the Tx antenna.

One needs O-scopes, etc. to see this cause and effect, rather than waltzing around the house......